Wife's terrible stuffing appears to suppurate (6)
I believe the answer is:
fester
'to suppurate' is the definition.
('fester' can be a synonym of 'suppurate')
'wife's terrible stuffing' is the wordplay.
'stuffing' indicates the answer is hidden within the clue.
'FESTER' is hidden within 'wifes terrible'.
'appears' acts as a link.
(Other definitions for fester that I've seen before include "Suppurate" , "Rankle" , "Of wound, become septic and filled with pus" , "Rot" , "Decay" .)